C. NAUSEOSUS. 209 



They are practically confined to the mountains of California from the chaparral belt 

 upward, monocephalus in particular reaching timber-line. 



While Chrysothamnus parryi is browsed more or less during drought periods, especially 

 the abundant typicus and howardi, it is to be regarded as a range weed, valuable only as 

 an indicator of the degree to which over-grazing has proceeded. 



12. CHRYSOTHAMNUS NAUSEOSUS (Pallas) Britton, in Britten and Brown, III. Fl. 3:326, 

 1898. Plates 33 to 35. 



Shrub usually 3 to 20 dm. high, but varying from mere dwarfs to arborescent forms 25 

 dm. high, commonly with several erect stems from the base, these branching to form 

 rounded bushes; bark of main stems brown, fibrous; twigs flexible, erect, moderately 

 leafy, covered with a closely packed gray-green or white felt-like tomentum, which is 

 deciduous only after several years, striate when the tomentum is smooth-surfaced but the 

 striae masked when the surface is loose and fluffy; leaves varying from nearly filiform to 

 broadly linear, not twisted, acute, 2 to 7 cm. long, 0.5 to 5 mm. wide, 1- to 3-nerved, not 

 rigid, more or less tomentulose but sometimes practically glabrous; heads in terminal 

 rounded cymes, these sometimes compound and forming elongated round-topped thyrses; 

 involucre 6 to 13 mm. high; bracts usually 20 to 25, in vertical ranks, lanceolate, acute or 

 obtuse, firm, glabrous to densely tomentose, without herbaceous tips; flowers usually 5, 

 rarely 6; corolla tubular-funnelform, passing imperceptibly from tube to throat, 7 to 10 

 or rarely 12 mm. long, either glabrous or puberulent or arachnoid-pubescent on the tube; 

 lobes 0.4 to 2.5 mm. long, erect to spreading, glabrous or sparsely pubescent; anther-tips 

 lanceolate, acute, 0.4 to 0.7 mm. long; style-branches long-exserted, the linear-filiform 

 acute appendage nearly equaling or usually much exceeding the stigmatic portion; 

 achenes narrowed below, 5-angled, 5 to 5.5 mm. long, densely strigose or subvillous to 

 glabrous; pappus shorter than or slightly exceeding the corolla, comparatively rigid, 

 dull white. (Chrysocoma nauseosa Pallas in Pursh, Fl. Am. Sept. 2:517, 1814.) 



On the plains and in the mountains, chiefly of the Great Basin area, but extending 

 from Saskatchewan and the Dakotas to Colorado, western Texas, northern Sonora, Lower 

 California, the inner Coast Ranges of upper California, eastern Washington, eastern 

 British Columbia, and Alberta. 



SUBSPECIES. 



The specific limits here set for C. nauseosus are somewhat more extended than those 

 assigned in any previous treatment, excepting only a recent one by Hall (Univ. Calif. 

 Publ. Bot. 7:159 to 181, 1919). The species comprises a multitude of forms, from 

 among which 47 segregates have been technically described. All but eight of these have 

 been accorded specific rank at one time or another. The difficulties encountered in an 

 attempt to assign specific or even varietal rank to all of the forms is indicated by the 

 following quotation from page 161 of the paper just referred to: 



"Notliing can be more certain than that these forty-two [now forty-seven] attempts to recognize species 

 and varieties do not by any means exhaust the resources of the group. Every autumnal excursion into a new 

 district brings to hglit one or more forms not previously described. The only limits set to the number of new 

 species or varieties which might be set up lie in one's ability to visit all parts of the field during the flowering 

 period and the failure or disinclination to recognize minute variations. But the systematist should include 

 in his ultimate object not only the recognition of this multitude of forms, but also their proper arrangement 

 in a scheme which will display their natural relationships. Since this would entail an enormous amount 

 of detailed labor, including extensive experiments, and since the results, even if attainable, would be of but 

 little practical value at the present time, the writer has satisfied himself with the acceptance of twenty-two 

 forms, all of which are treated as varieties. This is believed to provide for all of the principal forms, and 

 it is quite certain that each of the described varieties is a natural unit, although in most cases it is itself made 

 up of still smaller variants." 



